Loom harness mechanism.



L. S; BURBANK.

LOOM HARNESS MECHANISM.

' Patented Oct. 18,1910.

HHH

LUS S. BURBNK, 0F HGPEDALE, MASSACHUSETTS, ASSllG'NR TO DRLER GOMPANY, 0l? HOPEDA'LE, MASSACHUSETTS, A 'CORPQRTON F MAINE.

LGGM HARNESS MEUHANSM,

Specification of Letters latent.

latented @en isili).

Application filed April 27, 1910. Serial No. 557,877.

.To uit whom it may com '"n:

Be it known that l, Louis S. BURBANK, a eitizen of the United States, and resident of Hopedale, county oi. lVorcester, State of lilassachusetts, have invented an lmprovement in Loom Harness Mechanism, of which the following description, in connection with the accompanying drawing, is a specification, like characters on the .drawing representing' like parts.

Ylhis invention relates particularly to that type ci shed forming mechanism wherein the loom-harness is moved positively in one direction and is spring-actuated in the opposite direction. 4

My invention has for its object the production of loom-harness mechanism of such type so constructed and arranged that the alternate expansion and contraction of the actuating spring is materially reduced in extent and the variations in tension more evenly distributed or equalized throughout the movement of the harness in either direction.

As the movement of a harness is individualized or effected independently of its fellows in a set my invention is adapted for use With any desired number of harnesses.

ln the present'embodiment of my invention the harness is depressed by usualcamactuated means, and it is lifted by the contraction of an overhead lifting spring fixedA one end and connected atits other end with the top of the harness, the intervening c' connections including means to minimize the elongation and contraction of the spring. and to substantially equalize the tension thereof as 'the harness rises and falls.

As is Well known to those skilled in the art the resistance or tension of the usual coiled lifting spring gradually increases with the elongation as the harness is depressed, while such tension gradually decreases as the spring contracts during the lifting of the harness, and not only 1s the change in the length of the spring very eX- tensive but the movement of the harness is neither smooth nor regular, because of the Wide variations in tension. The springs tend to jump, and they are as a rule shortlived, the breakage-apparently being due to crystallization ot the metal resulting from rapid, sudden and marked variations in tension. Ey my present invention I am enabled to overcome these objections, and

as the changes in the .length of the spring are very much reduced in extent and the tension thereof substantially-1 equalized throughoutthe stroke of the li'arness the tendency to crystallize is minimized so that very little breakage occurs.

The various novel features of my invention will be fully described in the subjoined specification and particularly pointed out in the following claims.

l have illustrated my invention in connection With a two-harness set, as sufcient for a complete understanding thereof but it will be apparent hereinafter that the invention is equally Well adapted for use With any desired number of harnesses. y

Figure 1 is a front elevation of a suliicient portion of the shedding mechanism of a loom embodying one form of my invention, the depressing cams being omitted; Fig. 2 is a side elevation on a smaller scale of the harness-cams and the usual treadles ooperab ing therewith; Fig. 3 is an enlarged view of what l have termed the compensator, to be referred to; Fig. Il is a similar view of a slightly modied form of compensator', to be referred to.

lieferrin to Fig. l the overhead arch A, the gui( e-sheaves B, B over which pass the sides I), b of the flexible bridle attached to the top bar of each harness, the front and back harnesses H, H and the stirrups t, t connecting the bottonrbars of the harnesses with the treadles T, T', and the depressing cams C, C', Fig. 2,' on the camshaft C", may be and are all of Well known or usual construction. It will be understood that a pair of the guide sheaves B, B Will be provided to cooperate Wit-h the bridle of each harness, as is usual, although to avoid confusion l have not attemped to show the bridle for the back harness H. An upright bracket 1 on the arch sustains thejournal 2 'for the series of sheaves B and above the latter the bracket has lugs 3, 3 one above the other for the shackles of the fixed ends of the overhead, coiled lifting springs S, S', one for ,each harness. At the opposite side of the arch A is arranged a second bracket 4 which lsupports thestud 5 for the series of sheaves B, said bracket having an upwardly inclined, lateral extension 6 rovided with a frontwardly projecting horizontal vstud 7, on which are mounted the `oscillating compensato'rs, sani compensators being arranged ESO sie

sideby side and each one forming a part of the connections between a lifting spring and its harness, each compensator being thus located above and at one side of its harness and substantially in the plane thereof, econoniizing space.

For convenience the compensators in Fig. l are indicated by the reference letters D, D', but as they are alike only one need be described in detail. Each compensator is a cam-like member, made of suitable 1nnterial of requisite thickness to provide a working edge or face of suitable Width, having asegmental portion from 8 to 9 of uniform and relatively large radius, Fig. 3, and a ortion of a gradually but rapidly decreasing radius from 9 to 10, a pin 1l iiXedly secured to the compensator` extending from the cam surface beween the points 9 and 10, as shown. The effective portions of the cam surface of the compensator are 'from 8 to 9, and from the pin 1l to the point l0, and it will be seen that the radius of said Alatter portion decreases from the pin 1l to the point l0, whileothe radius of the segmental portion 8-9.is uniform. The compensators are mounted to oscillate onthe stud Tand herein Ihave shown a continuous `Xible member between the free end of a lifting springvand the bridle of its harness, passed around the cam surface of the compensator and fixedly attached thereto by the pin ll, but for convenience I designate the part s of said member, between the spring and compensator, as the spring connector, and the part 71,l between the bridle and the 4compensator as the harness connector. i y y Referring now to-Fig. 1 it will be seen that the spring connector s passes around and coperates with the part of the cam surface of thecompensator between pin 11 and the point 10, while the harness connector passesaround and coperates with the partA8-19uof uniform radius. The front harness H"'is up and its lifting spring S is A contracted; but with suilicient tension still exerted to maintain the harness lifted. Now when said harness is depressed the pull transmitted through the bridle to the connector h and in 11 operates to revolve the compensator in the direction of arrow v13, Fig. l, and as the harness descendsthe connector it will be given olf at a uniform rate due to its coperation with the circular arc.

8 9 of the compensator'until the compensator D assumes the angular position of the compensator D", Fig. l. As the compensator thus revolves the pin 1l acts through xthe connectors to stretch or elongate the spring S, but asthe coperating part of the cam surface of compensator D from pin 11 to point 10 is of gradually decreasing'radius the lever arm acting on the harness con! nectar s is gradually but quite rapidly short-l ening, as the decrease in radius is rapid.' Consequently, for a given angular movement of the compensator the spring connector s is taken up to a much less extent than the harness connector It is given ofi, and there is a relatively small elongation of the spring as compared with the stroke of the harness, and as the lever arm between the axis of the compensator and the point on its cam surface at which the connector s engages is gradually decreasing the tension of the spring is equalized as it elongates. In other words, while the resistance of the spring tends to increase with its elongation the elongating force acts with a decreasing leverage, or effect, and a balancing or equalizing is thereby effected, so that the resistance offered by the spring to the descent of the harness is' made substantially uniform throughout the stroke.

The Aposition of the connector s between the spring S and its compensator D is shown in Fig. l wherein the corresponding harness H is depressed, and it will be seen that said connector s at such time very closely approaches the axis ofy the compensator D. As the harness rises its compensator revolves oppositely to' arrow 13, Fig. l, and the harness connector IL is taken up more rapidly than the spring connector 1s given off, and at the same time the leveracts upon' the compensator ra idly increases until theharness, s at its j lriligh point, and while the, lifting force, or.l tension of the spring diminishes-as itV contracts. it acts through an increasing' leverarmythus effecting the equalization .on fthe up-stroke of the harness. Owing vto the camlike actin@ 4surface of the .compensator there is a di 'erential longitudinal movement of the attached harness andspring connectors, in opposite directions, the former movin at a faster speed, and the leverage for the iarness connector is greater than the maximum leverage for the spring connector, as will be manifest.

In Fig. 4 the compensator D t mental portion from 2O to 25, cooperating with the harness-connector 71 as before, but the upper part of the compensator is built out, at dx, with a radius gradually decreasing from 30 to 35, forming the surface which cooperates with the spring connector s, a step being formed between` tlie points 20 and 30.

The operation is the same ashas been dehas a seg-y -scribed, but by the constructinn shown in Fig. 4 I can get a veryQ rapid and material variation in the radius of the part of the compensator which coperates with the spring connector, which is desirable in some harness motions. It will be seen that a relatively small change in the lengthvof the lifting spring is effected as it is elongated and contracts, and this not only prevents the spring from thrashing about, but, in connection witli the equalizing of the ltension, obviates the tendency to `rapid crystallization of the spring and consequent breakave. f

l:The mechanism is very simple and effective, it consists of few parts, and it is compact and direct acting, and as theilexible connectors copera'e only with curved portions of the compensator there is no sudden or sharp bending, and thereby wear and te'ar is very much reduced.

Various changes or modifications may be made by those skilled in the art without dev parting from the spirit and scope of my invention as set forth in the claims annexed hereto.

Having fully described my invention, what I claim as new and desire to secure by Letters Patent isz*- f l. rI`he combination with a verticallymovable loom-harness, and means to depress it, of an overhead lifting spring, an. oscillating cam-like compensator located above and at one side of the harness, a flexible connector between the compensator and the. spring, and a flexible connector between said compensator and the harness, the surface of the compensator cooperating with the harness Vconnector having a uniform radius, and that'part of the surface cooperating with the spring connector havinga varymg-radius, the spring connector moving toward the axis of the compensator asthe latter is turned toI elongate the spring, said connectors extending inward from the top and bottom of the compensator and above the harness.

40 2. The 4combination with a` verticallymovable loom-harness, and means to de ress it, of an overhead, laterally extended li ting' the edge eectivelycoperating ,with the other connector having a uniformprafdius,

the compensator lying between the connectors.

3. The combination with a verticallymovable loom-harness, and cam-actuated means to depress it, of overhead sheaves, straps attached to the top of the harness and led over said sheaves, an oscillating compensator at one side of the sheaves, having a lower segmental portion Iof its face of relatively large and uniform radius and an upper portion of its face of 'a varying radius, the greatest radius of which is near,4

a lifting spring above the sheavesand fixed at one end, and a flexible connector attached to the free end of the spring and to said compensator and passing over the part thereof having a varying radius, to reduce the changes in the length of thes'pring and equalize the tension thereon as the harness rises and falls, said connectors extending inward from the compensator and located one above the other.

4. The combination with' a verticallymovable loom-harness, and cam -actuated means to depress it, of an overhead lifting spring, overhead sheaves, a bridlev led thereover and attached to the harness, an oscillating, cam-like compensator at one side ofthe sheaves having a circular portion of relatively large radius and a portion of varying radius less than that of the circular portion, and a flexible member connecting `said bridle and the spring' and passing around said 'portions ofthe compensator, and fixedly attached tothe latter between such portions', the circular portion actin upon tha-t part of said flexible member lea ing to the bridle and the portion of varying radius acting on that part of the member leading to thespring.

. In testimony; whereof, I have signed my name to this specification, in the presence of two subscribing witnesses. i

LOUIS S. BURBANK.

'I lVitnesses: i FRANK S. DU'rci-inn,

J. L. REMINGTON, Jr. 

